Few grading debates get as heated as the "no zeros" or minimum grading policy. Part of the heat comes from the label. It sounds like giving students points for nothing. The underlying argument is about math.
The math problem with zeros
On a typical 100-point scale, A, B, C and D each cover about ten points. F covers sixty. That asymmetry means a single zero has an outsized pull.
A student who scores 90, 90, 90, 90 and then a 0 averages 72. Four A-level performances and one missing assignment produce a C-minus. Change that zero to 50, and the average is 82, still a clear drop but closer to what the student has shown they can do.
Put another way: it takes a lot of A's to climb out of one zero, but very few zeros to sink a string of A's.
Arguments for a floor
- Accuracy. Averages become closer to the student's typical performance.
- Recoverability. Students who fall behind early can still pass, which reduces the incentive to give up.
- Consistency with other scales. On a 4-point scale (A=4 to F=0), each grade is one step apart. A 50% floor is roughly the same idea applied to percentages.
Arguments against
- Effort signals. Teachers worry students will skip work if the cost is lower.
- Fairness perception. Students who did the work may resent peers getting 50 for nothing.
- Hidden problems. A floor can mask missing work in the grade itself, so you need another way to track it.
Making it work if your school adopts it
- Apply the floor to attempted work first. Many schools give 50 only for a genuine attempt and use an "incomplete" code for missing work that must be resolved by a deadline.
- Track missing work separately. Use the LMS's missing flag and contact families early, rather than relying on the grade to communicate it.
- Pair it with reassessment. A floor plus a clear retake policy turns "you can't fall too far" into "here's how you get back up."
- Explain it to students and families. Show the 90-90-90-90-0 example; it usually changes the conversation.
An alternative: change the scale
Some teachers sidestep the debate by grading on a 4- or 5-point scale, or moving to standards-based grading, where averages of zeros don't arise in the same way. If your school keeps percentages, a floor is one of the simpler ways to stop a single missing assignment from outweighing a semester of work.